The Karst Dynamic System of Vertical Zoned Climate Region: A Case Study of the Jinfo Mountain State Nature Reserve in Chongqing
垂直气候带岩溶动力系统特征研究——以重庆金佛山国家级自然保护区为例

Using data loggers recording with 15 minutes resolution, the authors made high resolution measurements of such groundwater parameters as the stage, pH, conductivity, temperature, and hydrochemistry at two locations within the vertical zoned climate region of the Jinfo Mountain Nature Reserve in Chongqing. The Bitan spring 700m a.s.l. represents subtropic climate, while the Shuifang spring 2000m a.s.l. represents plateau temperate climate. The results show that hydrochemical parameters of epikarst springs at different altitudes seem very sensitive to environmental change and are mainly controlled by two factors: air temperature and soil CO2 concentration. Lower altitude means higher air temperature and CO2 concentration, thus more active karst processes. Water temperature and pH of the Bitan spring show a remarkable diurnal variation with high value in the day and low value at night. During flood pulse, there are at least two effects influencing hydrochemistry of groundwater: dilution effect and CO2 effect. As a result, the pH of the Bitan spring drops while the conductivity falls. At the same time, the pH of the Shuifang spring rises, while the conductivity falls. These phenomena may indicate that the Bitan spring represents conduit-fissure flow and the Shuifang spring represents fissure media.